There are known switching devices for opening and closing an electrical line in which a strip-like contact piece is supported by an operating member that is translationally movable between a position in which said contact piece is applied to two contact terminals, thus closing the electrical line, and a position in which it is separated from said contact terminals, thus opening the electrical line.
During its translational movements, the contact piece is guided by rods along which it slides, to ensure the correct application of said contact piece against the contact terminals.
However, this guidance has the drawback that the friction occurring between the contact piece and its guide rods gives rise to dust that may be deposited on the electrical contact surfaces and may, in the long term, degrade the reliability of the switching device.
The applicant has proposed an improved solution to overcome these drawbacks, as described in patent EP 0670579B1. This solution is generally satisfactory for a large number of applications, since it proposes a switching device that can eliminate friction in the operating member. However, it may be unsuitable for applications at microwave frequencies of more than 40 GHz, for which the switching device, when in the closed position, must be capable of allowing signal transmission in the microwave frequency range above several tens of GHz, for example up to 60 GHz. This is because, in the disclosed switching device, some clearance may remain in the guidance of the push member, which gives rise to play at the end of the contact strip. Although this play is acceptable for most applications, since contact does in fact take place between the contact strip and the upper surface of the two contact terminals when the switch is closed, it may be unacceptable when the signals to be switched are very high frequency signals.
Consequently there is a need to improve switching devices for opening and closing an electrical line, notably with the aim of providing effective transmission of signals in the hyperfrequency (HF) range above 40 GHz in the closed position.